1. Field of the Invention
The invention is concerned with the conversion of a feed which yields carbon on being heated above a carbonization temperature thereof and which is solid at ambient temperature, e.g., 20.degree. C., into a hot gas. The hot gas finds use in energy generation and chemical processing or the like. Valuable volatile chemicals and impurities may be separated from the feed while it is being heated and fed into the reactor wherein the carbonization and gasification occur.
2. Prior Art
The combustion and gasification of coal and other impure carbon containing fuels by carbonization and solution of the carbon in molten iron and its oxidation therein is known as a general process. The state of the prior art in this regard is set out, for example, by J. A. Karnavas, et al, in "ATGAS--Molten Iron Coal Gasification", 1972 AGA Synthetic Pipeline Gas Symposium, Chicago, Ill., Oct. 30, 1972, as well as in Pelczarski, et al, U.S. Pat. Nos. 3,526,478 and 3,533,739.
U.S. Pat. No. 1,838,622 discloses the method and apparatus of a vertical distillation-pyrolysis chamber linked to a combustion chamber. Some solids from the vertical chamber enter the combustion chamber and the gaseous products of combustion (non-combustible) directly heat the vertical distillation-pyrolysis chamber. The vertical chamber apparatus treats carbonaceous material, acts as a fractionator, and allows reflux of distillation products. The material proceeds by gravity flow through the column, the chamber fractionates volatile components, refluxing is provided to control the heat distribution within the column, heated gas may be introduced to heat material within the column, the process is continuous, and the column may be characterized as differential.
U.S. Pat. No. 1,759,821 discloses destructive distillation of carbonizable material in a retort in which material moves downward continuously and volatile components are fractionated.
U.S. Pat. No. 1,669,023 discloses carbonization and distillation of coal in a vertical chamber. Heat is supplied by upwardly flowing gas and gas may be added to points along the chamber to regulate the temperature distribution.
U.S. Pat. No. 3,109,781 discloses semi-continuous gravity flow of hydrocarboniferous material through a retort heated by injection of hot noncombustion-supporting gases at the lower end. Volatile components exit at the top end of the retort and enter a fractionator.
U.S. Pat. No. 3,838,015 discloses pyrolytic decomposition of trash in which air is admitted at a controlled rate to maintain combustion of gases produced and therefore regulate the pyrolysis temperature.
U.S. Pat. No. 3,886,048 discloses carbonizing and desulfurizing carbonaceous material by heating carbonaceous material admixed with iron in a reducing atmosphere and then subjecting the resulting char to an oxidizing atmosphere.
U.S. Pat. No. 2,787,584 discloses continuous carbonization of solid carbonaceous material by suspending the material in a moving molten stream at greater than 800.degree. C. An overhead stream of volatized chemicals and coke which is gravity separated from the molten metal are produced.
U.S. Pat. No. 3,890,908 discloses pyrolytic reduction of carbonaceous waste material by floating it up through a molten metal bath.
U.S. Pat. No. 1,734,970 discloses flow of carbonaceous material through a molten iron bath to produce volatile and nonvolatile products.
U.S. Pat. No. 2,953,445 discloses a two-chamber molten slag bath reactor for the production of water gas from a carbonaceous raw material. Gasification of the raw material and carburization of the bath occur in one chamber and combustion occurs in the other. Air or steam may be introduced into the bath through the walls of the bath or above the surface level of the bath (in the combustion chamber), the inlet being arranged tangentially so that the medium is set in circular motion between the chambers which are divided by gastight partitions.
Previously mentioned U.S. Pat. No. 3,533,739 discloses combustion of sulfur-bearing carbonaceous fuel by subsurface injection of the fuel and preheated air into a molten bath. Sulfur is extracted by the addition of lime and the main product of combustion is carbon monoxide. Carbon monoxide product may undergo combustion by injection of air. Heat combustion may be transferred to steam which drives power turbines.
U.S. Pat. No. 1,803,221 discloses apparatus and process for the production of hydrogen gas from methane-containing gases in a molten iron bath. The molten iron bath is divided into two parts by a partition wall which separate gaseous zones but leaves the molten iron free to circulate. Feed gas is blown in below the surface on one side of the partition and air is blown in on the other side. (The air may be blown in tangentially so as to cause the iron to circulate).
U.S. Pat. No. 1,592,861 discloses production of water gas by adding carbonaceous material to a molten bath, passing steam through the bath, maintaining bath circulation to promote absorption of incoming carbon into the bath. U.S. Pat. No. 1,592,860 discloses production of carbon monoxide by charging iron ore and coal or other fuel into a tower and allowing the mass to rest on the surface of the molten bath (held up by the buoyant force) followed by absorption of carbon into the bath and metal reduction.
U.S. Pat. No. 3,084,039 discloses blowing a stream of free oxygen-containing gas across the surface of a molten iron bath containing carbon to produce carbon monoxide gas.
U.S. Pat. No. 314,342 discloses manufacture of hydrogen gas by continuous introduction of carbonaceous material, simultaneously with steam, into a chamber containing a metallic oxide, followed by treatment of gaseous products with lime.
U.S. Pat. No. 3,933,128 discloses combustion of carbonaceous fuel dissolved in a molten salt to produce heat which may be used to generate steam to drive power turbines.
U.S. Pat. No. 2,876,527 discloses the cracking and dispersion of heavy hydrocarbon feedstocks in molten alkali metal carbonate baths followed by gasification of the dispersed material by contacting with oxygen, steam, or CO.sub.2 at 3000.degree. F. Cracking and combustion occur in separate vessels.
U.S. Pat. No. 3,933,127 discloses a means of sulfur removal from carbonaceous fuel during combustion. Fuel, a collector, and oxygen are introduced into a molten bath of salt. The collector forms a sulfur compound which is insoluble in molten salt.
U.S. Pat. No. 3,812,620 discloses the cooling of the outer metal shell of a molten metal bath by circulation of fluid through a plurality of passages within the shell. A layer of refractory material lies between the bath and the outer metal shell.